EP4448397B1 - Reusable plastic bottle - Google Patents

Description

Field of invention

The invention relates to a plastic bottle according to the preamble of claim 1 and to a method for manufacturing a plastic bottle according to the preamble of claim 15.

State of the art

Reusable polyester bottles sometimes need to be deodorized before refilling. These bottles are washed with an alkaline solution at 30 to 60°C and then refilled. At temperatures above 60°C, the bottles tend to deform or shrink excessively. Furthermore, the washing solution becomes more aggressive towards the polyester as its temperature increases, saponifying the ester bonds.

When polyester bottles are exposed to small, odor-intensive molecules (atomic mass unit less than 350 Daltons), these molecules migrate deep into the polyester matrix. The molecular components responsible for this can migrate into the contents and negatively affect the taste or smell of the contents, or indirectly, via the smell, the perceived taste of the contents.

The penetration depends on the contact time, the concentrations, and the temperature.

The washing process described above cannot completely remove the deeply penetrated molecules, meaning that once contaminated, bottles can never be completely freed from the unpleasant odors. If a reusable bottle is filled with a soft drink, limonene (136 Daltons) penetrates the polyester material. If this bottle is then refilled with mineral water, the limonene smell and taste are clearly noticeable and bothersome to the consumer. To avoid unpleasant odors and tastes, refillable polyester bottles are therefore only filled with the same product category, for example, always with soft drinks or always with water. Alternatively, a plastic bottle contaminated with odors can be removed from the refilling process after being tested with a so-called "electronic nose" by being discarded after the electronic nose has been used. Reasons for discarding include an intense odor, such as gasoline, urine, mildew, or rancid milk. etc. In particular, after misuse of the bottle by the end user, such penetration of odor-intensive molecules into the polyester matrix occurs.

In the US 2008/0032007 A1 This is a description of a plastic container for aroma protection of roasted coffee. The container is multi-layered and features an EVOH layer as a barrier layer.

From the DE 202 14 097 U1 A food aroma-preserving container, especially for ground coffee, is also disclosed. Because the container's outer shell is partially designed as a plastic bellows, the container volume can be adjusted to the volume of the contents, and the air space above the contents can be reduced to protect the aroma.

Object of the invention

The disadvantages of the described state of the art result in the task of creating plastic bottles in which unpleasant odors, based on small molecules that have penetrated deep into the polymer matrix, are no longer perceptible to the consumer, or of creating plastic bottles that are not rejected by the electronic nose located either before or after the bottle washing system.

The following features are described, which are to be considered (individually) as preferred features, even if they are not explicitly designated as such. The features are disclosed separately as part of any plastic bottle or any process for manufacturing a plastic bottle and – insofar as they are not mutually exclusive – in any combination. This includes the possibility of using device features to specify process features, and vice versa.

Description

The problem is solved in a plastic bottle by the features listed in the characterizing section of claim 1. Further developments and/or advantageous embodiments are the subject of the dependent claims.

The invention is preferably characterized in that coffee additives or coffee flavorings are added to the plastic, which reduces the penetration of the odor-intensive molecules into the plastic and reduces, masks or neutralizes disturbing odors of the odor-intensive molecules.

Therefore, coffee or, in particular, components derived from roasted coffee, especially coffee aromas or roasting aromas, or other components of the coffee beans themselves are added to the plastic.

These components include triglycerides, diterpene esters, diterpenes, triterpene esters, triterpenes and caffeine, as can be seen in the table below.

A disadvantage is that the use of roasted coffee additives leads, at least partially, to a reduction in the viscosity of the polyester. This reduction in intrinsic viscosity can amount to up to 0.6 dl/g as measured according to ASTM D4603.

The roasted aromas include the following, according to the table below:

Coffee additives are also understood to include waste products or unusable components of coffee or coffee beans. For example, fractions such as husks and skins are produced during the roasting process, which can be used according to the invention. Decaffeinated coffee produces caffeine as a waste product, and coffee grounds are left over after brewing. All these coffee components can be utilized according to the invention by incorporating them into the plastic.

The coffee components are added to the polyester in such a way that, at least for the consumer, no coffee or roasted aroma is consciously perceptible, and the electronic nose has stored this odor component as desirable.

Surprisingly, odors associated with bad or unwanted tastes (molecules smaller than 350 Daltons) penetrate the material significantly less, a fact clearly detectable by the electronic nose. More importantly, however, the human nose seems to no longer perceive these odors (molecules smaller than 350 Daltons), or at least much less, although it remains unclear whether this is due to neutralization or masking.

Roasted coffee, like vinegar, is a well-known home remedy for neutralizing odors. However, the reduced absorption of odor-intensive molecules observed in refillable bottles is quite surprising and has not been observed in other applications.

As described in the prior art, molecules that have penetrated deep into the plastic and produce unpleasant odors often cannot be removed by washing processes. Surprisingly, components of coffee can influence such odors to such an extent that they are no longer perceptible or only peripherally noticeable. This allows bottles to be refilled with different beverages without having to consider whether a strongly scented product was previously filled or whether the bottle might otherwise cause unpleasant odors for the consumer.

Even if odor-related pollution is unavoidable, it is less pronounced or only occurs after significantly more bottle cycles, ensuring that the bottle can go through more cycles before the electronic nose eliminates it.

The addition of coffee additives according to the invention has the advantage that almost all odors can no longer penetrate the polymer matrix as intensely and are therefore not released as strongly, and also the advantage that the remaining odors can no longer be perceived by the consumer with such intensity. In this case, one often speaks of a neutralizing effect of the coffee or the coffee aroma.

It is irrelevant whether unpleasant odors are masked or neutralized. What matters is that the consumer can no longer perceive them olfactorily, or at least not as strongly.

The addition of coffee additives means that the reusable bottle doesn't have to be filled with the same beverage every time; instead, the type of beverage can be changed. This is because any unpleasant odor of a beverage, which cannot be completely removed by cleaning the reusable bottle, is influenced or neutralized by the roasted aroma of the coffee. Furthermore, the penetration of odor-intensive molecules into the polymer matrix is reduced.

In one embodiment of the invention, the plastic bottle is made of a single layer of plastic containing coffee additives and/or coffee flavorings. In another embodiment, the plastic bottle is made of multiple layers, wherein at least the inner layer, i.e., the layer in contact with the contents, consists of a plastic to which coffee additives and/or coffee flavorings have been added. This is essential so that the coffee additives and/or coffee flavorings can prevent the transfer of an undesirable taste from the contents to the inner layer.

In a particularly preferred embodiment of the invention, the coffee additives are present in the plastic by incorporating roasted coffee or coffee production waste in free-flowing form, or liquid coffee extract from roasted coffee or coffee production waste, as the extraction material into the plastic. These two types of coffee additive reliably seal the polyester against new odors, reducing their penetration into the polymer and influencing the remaining release into the contents or the headspace above the contents, so that the consumer no longer perceives it as bothersome.

It has proven effective to add ground coffee beans or waste from coffee production with a particle size between 50 and 1000 nm to the plastic as a coffee additive in an amount between 0.1 and 5% by weight. The additive can be produced quickly and inexpensively, and small quantities are sufficient to achieve the desired odor reduction effect.

The coffee extract is preferably obtained by extracting finely ground coffee beans from heated oil or other fluid and is added to the plastic as an oil or fluid extract at a concentration of 0.1 to 2% by weight. The heated oil used as the extraction solvent could, for example, be rapeseed oil at 120°C. The oil extract disperses particularly easily and evenly in the plastic. It is also conceivable that the extraction solvent could be water-based. However, the extract must be made anhydrous before being added to the plastic, as water damages (hydrolyzes) the polyester.

It is advantageous for the coffee additives incorporated into the plastic to have a water content of no more than 2000 ppm. As explained in the last paragraph, only a practically water-free coffee component can be incorporated into the polyester without hydrolyzing it.

The invention is also preferably characterized by the fact that additional pure caffeine is incorporated into the plastic alongside the caffeine contained in the coffee additives. This additional caffeine significantly reduces the penetration of odor-intensive molecules smaller than 350 Daltons, such as limonene, acetaldehyde, formaldehyde, butyric acid, or valeric acid. Therefore, the odor load of a bottle is significantly reduced from the outset, and the roasted coffee aroma only needs to mask or neutralize lower odor concentrations.

In a preferred embodiment of the invention, the bottle is colored by the added coffee additives. The coloration from the coffee acts as a UV and light barrier. This coloration tends towards brownish or yellowish hues. As a result, a bottle containing coffee additives automatically acquires very good UV and light protection, which prevents the degradation of vitamin B2 in the product, e.g., milk. This degradation of vitamin B2, which leads to very unpleasant odors, can be significantly reduced by the coloring.

It has proven advantageous if the odor-intensive molecules include limonene, acetaldehyde, formaldehyde, lactic acid, valeric acid, or butyric acid. These molecules, which are regularly present in the contents, penetrate deep into the polymer matrix of the plastic bottle. Surprisingly, it has been found that these molecules penetrate the polymer matrix less, and the roasted coffee aroma is still present. It can neutralize very unpleasant odors. This allows the bottle to be refilled without the consumer perceiving the odors of the molecules.

Ideally, the plastic should be a polyester compound, in particular PET, PEF, PEN, or polyspirol alcohol polyester. This allows the coffee additive's mode of action to be applied to all common reusable polyester bottles.

The plastic can also preferably be a polyolefin, in particular PE, PP, or COC, which means that the principle of action of the coffee additive is also applicable to all common reusable bottles made of polyolefins.

In an advantageous embodiment of the invention, the polyester compound has an intrinsic viscosity between 0.84 dl/g and 1.40 dl/g according to ATM D4603. Compared to polyester compounds typically used for the manufacture of disposable plastic bottles, the present polyester compound exhibits an increased intrinsic viscosity. This compensates for the negative effect of the roasted coffee additives, which lead to a significant degradation of the polyester molecules.

In a further advantageous embodiment of the invention, the polyester compound has chain extenders. This also compensates for the negative effect of coffee components leading to a significant degradation of the polyester molecules.

A polyfunctional anhydride, i.e. a molecule with two or more anhydride groups, can preferably be used as a chain extender.

In a preferred embodiment of the invention, tetracarboxylic acid dianhydrides can be used as a chain extender.

In another embodiment, pyromellitic dianhydride can be used as a chain extender.

Furthermore, one of the following chain extenders can be used: bisoxazolines, bisepoxides, diisocyanates, polyepoxides, compounds bearing multiple glycidyl groups, maleic anhydride, phthalic anhydride, triphenyl phosphates, lactamyl phosphites, cyclo-phosphazene, polyacyllactam, as well as bis-2-oxazolines, bis-5,6-dihydro-4h-1,3-oxazines, diisocyanates, trimethyl 1,2,4-benzenetricarboxylate (trimethyl trimellitate, TMT), carbonyl bis (1-caprolactam).

It has been shown that the use of coffee additives and/or coffee flavorings, as well as possibly the use of higher viscosity polyester and the use of chain extenders, is appropriate for reusable containers because in the reusable sector bottles are used for numerous fillings and have a longer lifespan than disposable containers.

It is advantageous if the plastic is PET, but the effect of the coffee aromas is also relevant for PP and PE, especially HDPE or LDPE. Therefore, odor neutralization or masking can be applied not only to polyester bottles, but also to bottles made of polypropylene or polyethylene.

Another aspect of the invention relates to a method for manufacturing a reusable plastic bottle according to the description above. The bottle is manufactured by stretch blow molding an injection-molded preform. The preform is produced by forming an extruded polyester in an injection mold. During the filling of the extruder, coffee additives and/or coffee flavorings are added to the polyester. This allows the addition of coffee additives to be easily incorporated into each extrusion to produce a new preform.

Claims (15)

1. A reusable plastic bottle for receiving a product, which bottle consists of a plastic material that absorbs odorous molecules from the product or from residues of the product,
   characterized in that
   coffee additives and/or coffee flavors are added to the plastic material, thereby reducing the penetration of odorous molecules into the plastic and reducing, masking or neutralizing off-odors of the odorous molecules.
2. The plastic bottle according to claim 1, characterized in that the plastic bottle is designed in one layer from the plastic material with coffee additives and/or coffee flavors.
3. The plastic bottle according to claim 1 or claim 2, characterized in that the plastic bottle is multi-layered, at least the layer that is in contact with the product consisting of a plastic material to which coffee additives and/or coffee flavors are added.
4. The plastic bottle according to any of claims 1 to 3, characterized in that the coffee additives are present in the plastic material by introducing roasted coffee or waste from coffee production in a free-flowing form or liquid coffee extract from roasted coffee or from waste from coffee production as extraction material into the plastic material.
5. The plastic bottle according to any of claims 1 to 3, characterized in that the coffee additive is ground coffee beans or waste from coffee production having a particle size between 50 and 1000 nm and is added to the plastic material in an amount between 0.1 and 5 wt.%.
6. The plastic bottle according to any of claims 1 to 4, characterized in that the coffee extract is obtained by extracting heated oil or other fluid with finely ground coffee beans and is added to the plastic material as an oil or fluid extract in an amount between 0.1 and 2 wt.%.
7. The plastic bottle according to any of the preceding claims, characterized in that the coffee additives introduced into the plastic material have a water content of at most 2000 ppm.
8. The plastic bottle according to any of the preceding claims, characterized in that additional pure caffeine is introduced into the plastic material in addition to the caffeine contained in the coffee additives.
9. The plastic bottle according to any of the preceding claims, characterized in that the plastic material is a polyester compound, in particular PET, PEF, PEN, or a polyspiro alcohol polyester.
10. The plastic bottle according to any of claims 1 to 8, characterized in that the plastic material is a polyolefin, in particular PE, PP, or COC.
11. The plastic bottle according to claim 9, characterized in that the polyester compound has an intrinsic viscosity of between 0.84 and 1.4 dl/g according to ATM D4603.
12. The plastic bottle according to claim 9 or claim 11, characterized in that the polyester compound has chain extenders.
13. The plastic bottle according to claim 12, characterized in that a polyfunctional anhydride, i.e., a molecule having two or more anhydride groups, is used as a chain extender.
14. The plastic bottle according to claim 12, characterized in that bisoxazolines, bisepoxides, diisocyanates, polyepoxides, a plurality of compounds bearing glycidyl groups, maleic anhydride, phthalic anhydride, triphenyl phosphates, lactamyl phosphites, ciclo-phosphazene, polyacyl lactam, along with bis-2-oxazolines, bis-5,6-dihydro-4h-1,3-oxazines, diisocyanates, trimethyl 1,2,4-benzenetricarboxylate (trimethyltrimellitate, TMT), carbonyl bis (1-caprolactam) are used as chain extenders.
15. A method for producing a reusable plastic bottle according to any of claims 1-14, comprising the following steps:

    a) filling an extruder with a polyester,

    b) extruding the polyester and feeding the polyester into a molding tool of an injection molding machine,

    c) forming a preform,

    d) heating the preform to a temperature of 30 to 50° Celsius above the glass transition temperature of the polyester used,

    e) feeding the heated preform into a blow molding tool of a blow molding machine,

    f) blowing and stretching a plastic bottle, and

    g) ejecting the plastic bottle from the blow molding tool,

    characterized in that
    coffee additives and/or coffee flavors are added to the polyester when the extruder is filled.